It is known that various agents and certain organisms are capable of initiating ice nucleation. Ice formation is currently of substantial commercial interest as a factor in inducing frost injury to plants, in atmospheric precipitation processes and in commercial snowmaking. Various organisms have been identified having an INA wherein the DNA sequences encoding for the INA (usually a protein) are provided or introduced into a host organism. See e.g. U.S. Pat. No. 4,464,473 incorporated herein by reference, which describes various bacteria having an INA. The INA can be separated from the host cell but often times the host cell can be used directly as a source of the agent. Although some overwintering invertebrates are able to survive internal ice formation, most can not. Many of these freeze-intolerant invertebrates increase their cold tolerance by synthesis of antifreeze proteins and/or the accumulation of large amounts of glycerol and other low-molecular weight polyols and sugars. The synthesis of such agents allow supercooling of the invertebrate by as much as 25.degree. C. thus avoiding the injurious effects of such low temperatures, Baust et al (1985) Review--invertebrate Cold Hardiness: Facts & Fancy. J. invertebrate Physiol. 31:755-759. Of particular importance is the regulation of the temperature at which an invertebrate spontaneously freezes termed the supercooling point. As a freeze-intolerant invertebrate is cooled below 0.degree. C. it does not freeze immediately, but supercooling several degrees before ice nucleation (formation) occurs. Increases in the supercooling capacity have been correlated with evacuation of the gut in some species; however the precise mechanism affecting supercooling invertebrates is unknown e.g. Somme (1982) Comp. Biochem. Physiol.,73A 519-543.